1. Field of the Invention
The present invention relates to a transfer film, a method for manufacturing a laminate, a laminate, an electrostatic capacitance-type input device, and an image display device. In detail, the present invention relates to an electrostatic capacitance-type input device capable of detecting locations touched by fingers using changes in electrostatic capacitance, a laminate that can be used for the electrostatic capacitance-type input device, a transfer film that is used to manufacture the laminate, a method for manufacturing laminates using the transfer film, and an image display device including the electrostatic capacitance-type input device as a constituent element.
2. Description of the Related Art
Recently, in some of the electronic devices such as mobile phones, car navigations, personal computers, ticket vending machines, and bank terminals, a tablet-type input device is disposed on the surface of a liquid crystal display or the like, and, with reference to command images displayed on image display regions of the liquid crystal display, information corresponding to the command images can be input by touching places in which the command images are displayed with a finger, a stylus, or the like.
As the above-described input devices (touch panels), there are resistance film-type input devices, electrostatic capacitance-type input devices, and the like. However, resistance film-type input devices have a structure in which films are pressed down and shorted using a bilayer structure of a film and glass and thus have a disadvantage of a narrow operation temperature range or weakness to temporal changes.
In contrast, electrostatic capacitance-type input devices have an advantage since, simply, it is necessary to form a translucent conductive film on one substrate. As such electrostatic capacitance-type input devices, for example, there are electrostatic capacitance-type input devices in which electrode patterns are extended in mutually intersecting directions and input locations are detected by sensing changes in the electrostatic capacitance between electrodes when a finger or the like touches the input devices (for example, refer to JP2014-108541A).
In electrostatic capacitance-type input devices, a transparent film such as a transparent insulating layer or a transparent protective film for covering electrodes is formed.
Here, as smartphones or tablet PCs including an electrostatic capacitance-type touch panel on a liquid crystal or organic EL display, smartphones or tablet PCs in which reinforced glass represented by Corning's GORILLA glass is used for the front plate (the surface which a finger directly touches) have been developed and announced. In addition, smartphones or tablet PCs in which opening portions for installing pressure-sensitive (in which not electrostatic capacitance changes but pressure-sensitive mechanical mechanisms) switches are formed in a part of the front plate are commercially available. The reinforced glass has a high strength and is not easily processed, and thus, in order to form the opening portions, it is usual to form opening portions before a reinforcement treatment and then carry out the reinforcement treatment.
JP2014-108541A describes that, when a method for transferring a transparent film such as a transparent insulating layer or a transparent protective film which is intended to cover electrodes onto the electrodes from a transfer film is employed during the formation of the transparent film on a reinforced substrate having the above-described opening portions, it is possible to further prevent leakage or escape through the opening portions than cases in which a transparent film such as a transparent insulating layer or a transparent protective film for covering electrodes is formed using a coating method.
The transfer film described in JP2014-108541A is a transfer film having a temporary support, a first curable transparent resin layer, and a second curable transparent resin layer disposed adjacent to the first curable transparent resin layer in this order, in which the refractive index of the second curable transparent resin layer is higher than the refractive index of the first curable transparent resin layer and the refractive index of the second curable transparent resin layer is 1.6 or higher.
In addition, JP2014-108541A describes that the transfer film is preferably provided with a thermoplastic resin layer between the temporary support and the first curable transparent resin layer. Furthermore, JP2014-108541A describes the thermoplastic resin layer and describes that, for example, when a transparent laminate is formed by transferring the first curable transparent resin layer and the second curable transparent resin layer using the transfer film having the thermoplastic resin layer, air bubbles are not easily generated in individual elements formed by transferring the curable transparent resin layers, image unevenness and the like are not easily caused in image display devices, and excellent display characteristics can be obtained. In addition, the thermoplastic resin layer plays a role of a cushion material so as to be capable of absorbing protrusions and recesses (also including protrusions and recesses caused by images and the like which have been previously formed) on the base surface and preferably has a property of being capable of transforming in accordance with protrusions and recesses on subject surfaces. In addition, it is described that, in a case in which the layer thickness of the thermoplastic resin layer is less than 3 μm, the thermoplastic resin is not capable of sufficiently following protrusions and recesses during lamination and, in some cases, is not capable of fully absorbing protrusions and recesses on the base surface.
JP2013-218313A also describes in the same tone as JP2014-108541A that photosensitive films are preferably provided with a thermoplastic resin layer between a temporary support and a colored photosensitive resin layer (curable transparent resin layer).